A Weighted Composite Dose – Response Model For Human Salmonellosis

This article describes the development of a weighted composite dose – response model for human salmonellosis. Data from previously reported human challenge studies were categorized into two different groups representing low and moderately virulent/pathogenic Salmonella strains based on a disease end point. Because epidemiological data indicate that some Salmonella strains are particularly pathogenic, and in the absence of human feeding study data for such strains, Shigella dysenteriae was used as a proxy for highly virulent strains. Three single-hit dose – response models were applied to the human feeding study data and evaluated for best fit using maximum likelihood estimation: (1) the exponential (E-1pop), (2) the two-subpopulation exponential (E-2pop), and (3) the Beta-Poisson (BP). Based on the goodness-of-fit test, the E-1pop and BP were the best-fit models for low and moderately virulent/pathogenic Salmonella strains, and the E-2pop and BP models were better for highly virulent/pathogenic strains. Epistemic analysis was conducted by determining the degree of confidence associated with the selected models, which was found to be 50%/50% (E-1pop/BP) for low and moderately pathogenic Salmonella strains, and 9.8%/90.2% (E-2pop/BP) for highly virulent strains. The degree of confidence for each component model and variations in the proportion of strains within each virulence/pathogenicity category were incorporated into the overall composite model. This study describes the influence of variation in strain virulence and host susceptibility on the shape of the population dose – response relationship.     

中国银行业竞争度测度模型改进研究

在对已有测度模型和测度指标进行比较分析的基础上，结合中国商业银行表外资产规模持续扩大、综合化经营水平不断提升、金融集团化日渐明显的发展趋势，对Boone指数的估计方法进行改进，并以2012—2018年60家商业银行的经营数据为样本进行实证研究，评估利率市场化对商业银行竞争度的影响。研究结果表明，模型类型会直接影响Boone指数的估计值，基于动态面板数据模型的估计值与随机效应模型、固定效应模型的估计值显著不同；随着时间的推移，资产规模并未随着效率的提升而增长，Boone指数呈下降趋势，银行业竞争度逐年下降；利率市场化完成之后，银行业竞争度并未上升，反而显著下降。从制度上解除利率管制并不能彻底扭转银行业竞争度不足的现状，还需要从扩大银行业对外开放、放松中小银行准入管制、硬化地方政府和国有企业的预算软约束等方面入手，进一步深化银行业市场化改革。     

凝聚随机算子的一个不动点定理

利用拓扑度的基本性质，给出了凝聚随机算子的一个不动点定理，由此推广了Altman定理，为进一步研究随机算子方程解的存在唯一性及解的近似方法提供了一个有力的工具。     

论《中美农业合作协议》对湖南农业发展的影响

《中美农业合作协议》及美方要价对湖南农业来说可谓是挑战与机遇并存 ,风险与希望同在。因此 ,湖南应充分利用四年的缓冲期 ,积极采取应对措施 ,趋利避害 ,以取得成功     

物理考核的一种量化方式

本文依据物理试题涉及的知识面和解题曲折程度，定认了物理试题难度的新概念，并从这种难度定义确定物理度卷的考核量，提出物理考核量化运作的一种新的方式。     

现代汉语兼语结构的机器探测

采用统计与规则结合的方法对现代汉语兼语结构的机器探测方法展开研究,提出了用于自动探测兼语的＂兼语候选项特征＂与＂支持度＂的概念,同时设计出了相应的算法,并在此基础上,用Visual C＋＋编译出了相应的＂现代汉语兼语结构机器探测软件＂。通过对200万字的《人民日报》1998年1月语料进行机器探测试验和测试,发现：对于现...     

应用灰色关联度分析法评价毛竹种源的研究

应用灰色关联度分析法，对毛竹9个种源10个测试指标进行了量化评估，通过各种源加权关联度的比较，较为全面、客观地评价了各种源在不同经营目标上的优劣，为确定适宜推广的种源提供理论依据。     

重庆市制造业的绿色经济增长核算:2001—2010

基于生产前沿理论的绿色经济增长核算模型,不仅将技术无效率和环境代价纳入了分析框架,而且还与"物质平衡思路"一致;该模型将绿色经济增长的源泉分解为环境约束下的技术进步、技术效率变化和资本深化3大部分。对重庆市27个制造行业的经验分析结论表明:经济增长中普遍存在着技术无效率现象,但50%以上行业的技术效率都得到了改善或维持不变;资本深化是经济增长的主要源泉,而技术进步主导的全要素生产率变动在其中的贡献相对较小;技术进步是引致全要素生产率增长的主要原因。为充分发挥重庆市制造业可持续发展潜力,后续发展中必须转变经济发展方式,在环境约束下走技术进步和技术效率改善的绿色全要素生产率增长之路。     

一类欧拉图的全着色

本文用构造性方法证得:对可由一点任意行遍的欧拉图,全着色猜想成立。     

Additive and Multiplicative Models and Multistage Carcinogenesis Theory

In light of the Armitage-Doll multistage carcinogenesis theory, this paper examines the assumption that an additive relative risk relationship is indicative of two carcinogens that affect the same stage in the cancer process. We present formulas to compute excess cancer risks for a variety of patterns for limited exposure durations to two carcinogens that affect the first and penultimate stages; and using an index of synergy proposed by Thomas (1982), we find a number of these patterns to produce additive, or nearly additive, relative risk relationships. The consistent feature of these patterns is that the two exposure periods are of short duration and occur close together.